Disk-knife holder.



J. BROOKS. DISK KNIFE HOLDER.

APPLICATION Hun APB,15.1907.

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JOHN BROOKS, OF BROCKTON, MASSACHUSETTS.

DISK-KNIFE HOLDER.

Specification of Letters Patent.

Patented Nov. 5, 1907'.

Application filed April l5. 1907. Serial No. 368.409.

To all whom it may concern:

Be it known that I, JOHN Bnooks, of Brockton, in the county of Plymouthand State of Massachusetts, have invented certain new and usefulImprovements in Disk-Knife Holders, of which the following is aspecication.

This invention relates especially to skiving machines, and consists of aholder by which the disk knife of such a machine may be secured andaccurately centered so that it will not work loose and give way while inuse.

The circular disk knives which are used for skiving frequently becomesomewhat distorted during the hardening and tempering so that the holesor eyes by which they are centered on the holding spindle lose theirtrue circular shape and become distorted. Thus after hardening they willnot tit an arbor upon which` they may have accurately fitted before thisoperation. Consequently it has usually been the practice hitherto tomake the eyes of such knives suiciently large before hardening so thatafter they have been hardened the eyes will still be large enough to tover the bushings or arbors made for them. As a result of course therewas always a certain amount of looseness which interfered with theproper grinding of the cutters and allowed them to slip and fail to workproperly.

It is my present object to provide a rotary holder which willautomatically center the disk, whatever may be the size and shape of thedistorted central hole, so that there will be no opportunity for it toslip and vibrate laterally. Accordingly I provide the holder constructedas hereinafter described and claimed and substantially as shown in thedrawings.

Of the accompanying drawings-Figure l represents a sectional view of acutter holder and cutter applied thereto. Fig. 2 represents a sectionalelevation on an enlarged scale, of the centering device of the holderand the manner in which it operates. Fig. 3 represents a sectionalelevation showing a modification.

The same reference characters indicate the same parts in all thefigures.

Referring to the drawings, the main portion of the holder consists of aspindle a which is adapted to be driven rotarily in bearings in themachine, and has a head or flange b provided on its outer end with afiat bearing surface c perpendicular to the axis of the spindle. Theupper side of the disk knife ci is adapted to have a bearing against theface c near the periphery thereof.

The spindle is tubular, having a central bore through which passes theshank e of a retainer for the cutter which has on its outer end a head fadapted to bear upon the under side of the disk knife and hold thelatter against the face c. As appears in Figs. l and 2, the upper orinner face of the head f is flat and extends in a single plane from theshank to the periphery of the head, being therefore parallel with theface c.

A portion of the bore of the spindle is enlarged to a greater diameterthan that of the shank e, and in this enlarged portion is located asleeve g which surrounds the retainer shank and occupies the spacebetween the latter and the sides of the spindle. This sleeve has on itsouter end a head h which is beveled so that its tip has the shape of acone frustum represented at t' in Fig. 2. The greatest diameter of thehead h is greater than that of the eye of any cutter for which it isadapted, while the diameter at the outer end is less than the eye of anysuch cutter. The length of the conical portion also is at most nogreater than the thickness of the disk knife, so that when it enters theeye of a cutter, it will engage the edges of the same before its endemerges from the under side of the eye.

Within the cavity or chamber j of the spindle back of the centeringsleeve g is a spring [c which surrounds the retainer shank and bears atone end against the sleeve while its other end is arrested by theshoulder Z. This spring forces the sleeve outward toward the retainerhead f and serves to hold the cone frustum z' in firm engagement withthe edges of the cutter eye. The sleeve and spring are retained in thechamber and the cutter held against the surface of the spindle head b bya nut rm, which engages the threaded end n of the retainer shank anddraws the head thereof against the cutter', clamping the latter againstthe spindle. In Fig. 3 the separate nut m is omitted and the retainer isheld in place by the engagement of its threaded ,end with internalthreads formed in the end of the spindle. The retainer' is fastened inplace by being turned by a screw-driver which can be inserted in a sloto in the head f.

It will be seen that the centering sleeve is always held in engagementwith the central hole of the cutter with which it makes contact at threeor more points so that the cutter cannot possibly move sidewise afteronce being clamped in place. As the conical portion of the sleeve is ofless length than the thickness of the cutter and does not protrudethrough the eye of the cutter, there is no necessity of forming anannular recess or groove to receive the same in the head of the retaineraround the shank thereof; consequently the clamping surface of thisretainer head may be made plane, as hereinbefore described and given abearing on the entire area of the cutter which it overlaps.

I claim:-

l. An attachment for skiving machines, comprising in combination, along' tubular spindle adapted t0 he contained in a bearing in the headof a skiving machine, a laterallyextending wide flange on the end ofsaid spindle having a piane surface at right angles t0 the spindle axis,a thin wide disk knife bearing against the plane surface of said ilangenear the periphery of the latter', a centering sleeve within the bore ofthe spindle having a greater diameter' than the eye of the knife andformed with a conical zone on its outer end of a height not greater thanthe thickness of the knife and tapering to a less diameter than the eyethereof, yielding means tending to force the conical end of said sleeveout of the spindle and into the eye of the knife, and a retainerl havinga shank passing through the spindle and secured at the remote endthereof, and a head pressing the knife against the bearing surface ofthe flange, whereby the knife is held firmly with its circular edge in aplane perpendicular to its axis of rotation.

2. A disk-knife holder for skiving'machines, comprising a tubularspindle having a bearing surface at one end, a retainer provided with ahead adapted to hold a diskknife against said bearing surface and ashank passing through the bore of the spindle, a centering sleeve withinthe bore of thespindle having an external bearing on the inner surfaceof the spindle so as to he held centrally therein, and formed with atapered end, and yielding means pressing said tapered end toward thehead of the retainer and into the eye of the disk to center the saine,said sleeve having a diameter as great as that of the eye at a lessdistance from its end than the thickness of the disk.

3. A rotary cutter holder, comprising a tubular spindle having a flangeat one end with an outer plane abutting surface for the cutter, aretainer having a shank adapted f to be held Within the bore of thespindle and having a head with a surfaceextending in one plane from theshank to the periphery thereof, opposed to the abutting surface of thespindle flange for clamping a cutter against the latter, and a centeringsleeve contained within the bore of the spindle surrounding the retainershank and yieldingly impelled outward toward the head of the retainer,said centeringsleeve being tapered at its outer end and of such diameteras to contact with the rim of the eye of the cutter before beingprojected entirely through the same.

-L A rotary cutter holder, comprising a tubular spindle adapted to beheld rotatably in bearings, having at one end a transverse abuttingsurface for the cutter and a central cavity of greater diameter than thebore of the spindle, an integral shoulder between said bore and cavity,a retainer having a shank adapted to be passed through said bore and ahead for clamping the cutter against the abutting surface of thespindle, a centering sleeve having a tapered end for entering the eye ofthe cutter, located within said recess, and a spring also located insaid recess and pressing against said shoulder and sleeve for projectingthe tapered end of the latter into the eye of the cutter.

In testimony whereof I have aixed my signature, in presence oi twowitnesses.

JOHN BROOKS.

Witnesses A. C. RATIGAN, ARTHUR H. BROWN.

